Different guns totally different point blank range. My .44 mag is sighted in to be dead on at 100 yards. My 30-06 is sighted dead on for 200 yards. My weatherby 338/378 is sighted in for 400 yards.
What I am saying is there is a whole bunch of variables. Velocity, bullet weight, Bullet shape/coefficient, No one rule fits all cases. I always sighted in for 2" high at 100 yards till I started shooting a lot more than once a year. It worked at the time, but I never shot beyond 150 yards either. Most shots were at 80 yards. Back then I only had one gun, a .308. Today I have specialty guns some for devastating effect at close range, 15 to 30 yards. (45-70, 350 Rem Mag Black Bears over bait). Others for shooting moderate ranges, 25-06 30-06 500 to 700 yards. Then long ranges 337/378 Weatherby out to 1000yards.